The present invention relates to a friction stir welding apparatus, and more particularly relates to a friction stir welding apparatus having a displacement detection device.
In recent years, in addition to general arc welding and the like, there has been proposed a friction stir welding apparatus that performs friction stir on a predetermined weld portion in a processing target component formed from a plurality of metal plates such as aluminum plates by using a probe rotating at a high speed, and that welds the metal plates to each other. A configuration including a weld portion welded by the friction stir welding apparatus has been realized even in strength components of a mobile object such as an automobile.
In such a friction stir welding apparatus, it is necessary to move the probe and the processing-target component relatively to each other, and precisely weld a predetermined weld portion. Therefore, it is important to move the probe and the processing target component relative to each other accurately without unnecessarily causing relative displacement therebetween.
Under such circumstances, Japanese Patent Application Laid-open Publication No. H6-87075 relates to an inclination control welding method, although does not relate to a friction stir welding apparatus. Such a configuration is disclosed in which a distance between a torch 1 and a workpiece 2 is measured momentarily by distance measuring sensors 15, 16, and 17 provided on right and left side surfaces and a front surface of the torch 1, and relative right and left inclination angles and longitudinal inclination angle of the torch 1 with respect to the workpiece 2 are controlled so that the torch 1 and the workpiece 2 can be held at predetermined angles, respectively, based on the measured values. Furthermore, right and left absolute angles and front and rear absolute angles of the torch 1 are measured momentarily by a torch inclination measuring sensor 18 provided on the top of the torch 1, and an optimum welding condition depending on the absolute angles of the torch 1 is selected from welding conditions by the absolute angles of the torch 1 based on the measured value, thereby executing control.
Japanese Patent Application Laid-open Publication No. 2004-136365 relates to a friction stir welding apparatus 20 and discloses a configuration including a tool-rotation drive unit 24, a tool-displacement drive unit 25, a tool movement-amount detecting unit 40, a welding-pressure detecting unit 41, a deflection-correction-data accumulating unit 42, a welding-condition-data accumulating unit 43, an inter-tool distance obtaining unit 44, a deflection-amount calculating unit 45, an input unit 46, a display unit 47, and a control unit 48. The deflection-correction-data accumulating unit 42 compiles a database and accumulates a deflection amount δ of the friction stir welding apparatus 20 with respect to a welding pressure F1 of a welding tool 21, and the deflection amount δ is obtained in advance by experiments. The deflection-amount calculating unit 45 extracts the deflection amount δ from the deflection-correction-data accumulating unit 42 based on a detection result provided by the welding-pressure detecting unit 41. It is also disclosed that the deflection amount δ is actually measured and stored.